Monoazo dyestuffs



Patented June 3, 1952 MQ QAZ E U F$ Harry W. GrimmeLfProvidence', B. I.,.IJudw.ig

Richter; Easton, Pa., and Jack M mar, l \l;gY., assignors to General Anil Corporation, elaw o an el-1 nc. & F m

New Xork, NQYI, a corporation No Drawing. Application June 8, 1950,

Serial No. 166,986 z 1 Claim. (01. zoote) I The. present invention relates to monoaz o dyestufis containing an N-phthaloyl-amino-hydroxynaphthalene group, said dyestuffs being capable of being converted into their metal complex compounds, in which form they yield valuable dyeings of excellent fastness properties.

It has been proposed to produce monoazo dyestuiis capable of being converted into their metal complex compounds and containing an N- phthaloyl amino hydroxynaphthalene group. The dyeings obtained with these dyes are characterized as being of excellent fastness to milling. The prior art required that the dyes be produced by the reaction of a diazotized o-aminophenol free from sulfonic acid groups with the aforestated N-phthaloyl-amino-hydroxy-naphthalene. It has been discovered, however, that the manufacture of these dyes proceeds only with great difiiculty and always with marked decomposition. As a consequence, the yields are low and the resulting dyes are quite expensive. Furthermore, the dyeings produced from such dyes have the disadvantage that they change their shade when viewed under artificial light.

Surprisingly, we have found that all of the difficulties encountered in the preparation of the prior art products and in the dyeings obtained therewith can be avoided if there be used for the preparation of the dyes the diazonium compound from 4-chloro-2-amino-l-hydroxybenzene-fi-sulfonic acid, on the one hand, and l-N-phthaloylamino-'7-hydroxy-naphthalene, on the other hand. Thus the formation of the dye is surprisingly energetic. The formation of by-products is avoided and as a consequence the yields are materially higher. The final cost price of the dyestufi is also much lower. Furthermore, the dyeings obtained from the metal complexes of such dye are not only extremely fast to light and fulling, but have the extremely important property of retaining their shade when viewed under artificial light. They furthermore have the great advantage that they dye wool according to the monochrome process in full and pleasing shades of outstanding fastness properties,

2 the shades of such dyeings likewise being. uhaffected when" scanned under artificial light.

Such dye and the metal complexes thereof constitute the purposes and objects of the present invention.

The dyestuffs, the metal complex compounds of which yield the aforesaid valuable dyeings may be characterized by the following general formula:

OH OH HOaS -N=N C O OH The monoazo dyestufi may be metallized on the fiber or in substance according to the customary manner. The usual metallizing agents such as those of cobalt, chromium, aluminum, nickel and the like may be employed. The monoazo dye is made in the usual manner by diazotizing the amine with sodium nitrite and hydrochloric acid and coupling the resulting diazonium chloride in an alkaline solution. The alkali salts of the dye, when in the dry pulverized form, are generally dark powders soluble in water' dyeing wool from an acid bath gray to violet even shades.

The following example serves to further illustrate the invention but it is to be understood that the invention is notrestricted thereto. The parts are by weight unless otherwise stated.

Earample 22.4 parts of 4-chloro-2 amino-1hydroxybenzene- 6 sulionic acid are diazotized and coupled with 33 parts of l-N-phthaloylamino-lhydroxy-naphthalene in soda-alkaline solution at pH of 10.5. The coupling proceeds slowly but is ,finished overnight. When the combination is ,complete, the dyestuff formed of the formula:

' OH OH 1 l 1' HOiS =N HN $0 1 I -COOH is salted out if desired afteracidification, filtered ofi. and dried. It is a dark powder, soluble in water and dyes wool from an acid bath a violet shade. When after-treated with chromium salts according to the usual methods, a bluish black potting, and light.

The dyestufi, when applied according to the" monochrome dyeing method, yields on' wool bluish shade is obtained'of'very good fastness to falling, 'Y

grey e'ven shades of excellent fastness to light and fulling. The diazos obtained with such metallized salts do not change their shade in artificial light.

Various modifications of the invention will be apparent to those skilled in the art, and we accordingly do not intend to be limited in the patent granted except as necessitated by the ap-" pended claim.

This application is a division of our application 4 Serial No. 655,904, filed March 20, 1946, entitled Monoazo Dyestuffs, now abandoned.

We claim: The monoazo dye of the formula:

HOzS N=N COOH Name Date 1,078,925 .Kahn et a1. Nov. 18, 1913 1,411,245 Geldermann et a]. Mar. 28, 1922 1,925,434 Clingeslzein et al. Sept. 5, 1933 FOREIGN PATENTS 7 Number Country Date 7 Great Britain Oct. 2'7, 1930 

